The present invention relates to an optical system for shaping a laser beam and to a laser system having such an optical system.
On an incident interface, a laser beam is generally split into three parts: a first part is reflected at the interface (reflected laser beam), a second part passes through the interface into the second optical medium (transmitted laser beam) and a third part is absorbed at the interface (absorbed laser beam). An interface is defined as a surface that is arranged between two media of different refractive indices. An interface at which a laser beam predominantly passes from a first into a second optical medium is referred to as a transmitting surface. An interface at which a laser beam is predominantly deflected within an optical medium is referred to as a reflecting surface. The respective fractions of the reflected, transmitted and absorbed laser beam can be modified, for example, via the wavelength and/or the angle of incidence of the incident laser beam and/or via a coating of the interface.
U.S. Pat. No. 7,497,018 discloses a laser system in which a spot-shaped laser beam is reshaped by means of an optical system into a laser beam that is ring-shaped at least in some segments thereof. The laser system includes a housing, and a beam device arranged within the housing that comprises a beam source for generating a laser beam and the optical system. The optical system comprises a first optical element and a second optical element that is designed as a collimating lens, the optical elements being arranged in an optical mount. The beam source generates a divergent primary laser beam that impinges on the collimating lens which collimates the primary laser beam and generates a parallel laser beam. The collimated laser beam impinges on the first optical element which is arranged downstream from the collimating lens in a propagation direction and is designed as a conical mirror. A conical mirror is a reflective optical element that is designed at least in some segments thereof in the shape of a cone having a base and a lateral surface abutting the base. The lateral surface of the conical mirror is designed as a reflecting surface at which the collimated laser beam is deflected through 90° and reshaped into a laser beam that is ring-shaped at least in some segments thereof.
The known optical system for shaping a laser beam generates on a target surface a line-shaped laser mark. A shortcoming lies in that the optical system is not suitable to display in the laser plane, in addition to the line-shaped laser mark, also spot-shaped laser marks, which are suited, for example, for transferring right angles.
The aim of the present invention is to develop an optical system and a laser system having such an optical system, in which it is possible, in addition to displaying a line-shaped laser mark, to transfer angles from one target surface onto another target surface.
According to the present invention, a further optical element for shaping the at least segmentally ring-shaped laser beam is provided, the further optical element shaping the ring-shaped laser beam at least in some segments thereof in a plane parallel to the propagation plane. This embodiment has the advantage in that it is possible to generate spot-shaped laser marks on a target surface in addition to a line-shaped laser mark that the ring-shaped laser beam generates on the target surface. If two spot-shaped laser marks are arranged at a specified angle to one another, the angle can be transferred with the aid of the two spot-shaped laser marks from one target surface onto another target surface.
In a preferred embodiment, the further optical element for shaping the at least segmentally ring-shaped laser beam is integrated into the lateral surface of the first optical element or directly abuts the lateral surface. This embodiment has the advantage that the alignment of the optical elements relative to each other takes place during manufacturing of the optical system, rather than at a later time, and only one optical mount is required. The alignment effort required on the part of the user is reduced.
In a further preferred embodiment, the first optical element comprises a first lateral surface segment that generates the at least segmentally ring-shaped laser beam, and the further optical element comprises a second lateral surface segment, the second lateral surface segment abutting the first lateral surface segment. The first optical element is assembled from a plurality of segments that abut one another. In this arrangement the segments are selected such that they have the desired beam-shaping properties; a first segment produces a ring-shaped laser beam and a second segment produces a spot-shaped laser beam.
In a further preferred embodiment, a further optical element having at least one interface is provided, wherein the optical element for shaping the ring-shaped laser beam in a plane parallel to the propagation plane is integrated into the at least one interface, or directly abuts the at least one interface. Owing to the optical element for shaping the ring-shaped laser beam in a plane parallel to the propagation plane being integrated into an existing interface, alignment of the optical elements relative to each other takes place during manufacturing of the optical system, rather than at a later time; an additional optical mount is not required.
Particularly preferable, a further optical element for shaping the at least segmentally ring-shaped laser beam in a plane perpendicular to the propagation plane is provided, wherein the further optical element is integrated into the at least one interface or directly abuts the at least one interface. This embodiment has the advantage that a narrow line-shaped laser mark can be generated on the target surface. The ring-shaped laser beam is shaped, for example, with the aid of collimating optics or focusing optics. Owing to the further optical element being integrated into an existing interface, the alignment of the optical elements relative to each other takes place during manufacturing of the optical system, rather than at a later time; an additional optical mount is not required. The alignment effort required on the part of the user is reduced.
The optical element for shaping the ring-shaped laser beam in a plane parallel to the propagation plane and/or the further optical element for shaping the ring-shaped laser beam in a plane perpendicular to the propagation plane are designed preferably as diffractive optical elements, and are integrated into the lateral surface of the first optical element and/or into the at least one interface of the further optical element. Diffractive optical elements shape a laser beam in such a way that the zero order of diffraction of the laser beam generates a line-shaped laser mark on the target surface and the higher orders of diffraction; in particular the first order of diffraction, generate spot-shaped laser marks. An incident laser beam can be shaped with the aid of a diffractive optical element into nearly any desired beam distribution.
The optical element for shaping the ring-shaped laser beam in a plane parallel to the propagation plane and/or the further optical element for shaping the ring-shaped laser beam in a plane perpendicular to the propagation plane are preferably designed as ground optical elements. Spot-shaped laser beams can be collimated or focused by beam shaping optics. The beam shaping optics can be integrated into the ground optical elements via a curved incident surface.
In a preferred embodiment, the first optical element is designed as a base member having a lower base, an upper base, and a lateral surface abutting the lower and upper bases, wherein the lower base and the lateral surface are designed at least in some segments thereof as transmitting surfaces for the laser beam; the base member has a first cutout portion comprising a base that is arranged in the upper base of the base member and the lateral surface which is designed at least in some segments thereof as a reflecting surface for the laser beam. This embodiment has the advantage that only one optical mount is needed and that the alignment of the two optical elements relative to each other takes place during manufacturing of the optical system. The embodiment of the base member that has two transmitting surfaces offers the advantage that additional functions can be integrated into the base member or designed so as to directly abut the base member.
Particularly preferable, the base member has a second cutout portion comprising a lower base which is arranged in the lower base of the base member, an upper base which is designed at least in some segments thereof as a transmitting surface for the laser beam, and a lateral surface abutting the lower and upper bases which is designed at least in some segments thereof as a reflecting surface for the laser beam. The optical system thus has a first and a second reflecting surface for the laser beam, wherein the lateral surface of the first cutout portion arranged in the upper base forms the first reflecting surface, and the lateral surface of the second cutout portion arranged in the lower base forms the second reflecting surface. Owing to the double reflection of the laser beam, the optical system according to the invention is not sensitive to a tilting of the reflecting surface relative to the incident laser beam. Since the second reflecting surface is likewise integrated into the base member of the optical element, only one optical mount is needed and the alignment of the first and second reflecting surface relative to each other takes place during production of the first and second cutout portion in the base member.
Particularly preferably, the first cutout portion of the base member has an upper base that is parallel to the lower base, which upper base is designed at least in some sections thereof as a transmitting surface for the laser beam. This embodiment has the advantage that a spot-shaped plumb beam is generated in addition to the ring-shaped laser beam. The beam shape of the plumb beam can be adjusted via an optical element that is integrated into or directly abuts the upper base. A collimated or focused plumb beam can be generated by collimating or focusing optics.
Also provided is a laser system comprising a beam source for generating a laser beam and comprising the optical system according to the invention. Preferably, an adjustment device is provided whereby the position of the beam source relative to the optical system and/or the position of the optical system relative to the beam source are adjustable in a propagation direction of the laser beam and/or in a plane perpendicular to the propagation direction of the laser beam.
In a preferred embodiment of the laser system there is provided a first optical system which produces a first at least segmentally ring-shaped laser beam and at least one spot-shaped laser beam, and at least one further optical system which produces a further at least segmentally ring-shaped laser beam and at least one spot-shaped laser beam.
Particularly preferred is a third optical system which produces a third at least segmentally ring-shaped laser beam and at least one spot-shaped laser beam. The ring-shaped laser beams are arranged perpendicular to one another or at a specified angle.
In a further preferred embodiment of the laser system, at least one optical system is designed in such a way that in addition to an at least segmentally ring-shaped laser beam and at least one spot-shaped laser beam, both of which extend in the same propagation plane, a spot-shaped plumb beam is produced.
Embodiments of the invention will be described below with reference to the drawings. The drawings are not necessarily intended to show the embodiments true to scale, but instead the drawings are rendered, where expedient for explanation purposes, in schematic and/or slightly distorted form. With regard to teachings readily apparent from the drawings, reference is hereby made to the pertinent prior art for further details. One should bear in mind that a great variety of modifications and changes can be made with respect to the form and detail of an embodiment without departing from the general idea of the invention. The features of the invention that are disclosed in the description, in the drawings and in the claims may be essential for further enhancement of the invention, by themselves and/or in any combination thereof. Furthermore, the scope of the invention also covers any and all combinations of at least two of the features disclosed in the description, in the drawings and/or in the claims. The general idea of the invention is not limited to the exact form or detail of the embodiments shown and described hereinbelow, nor limited to a subject matter that would be limited when compared to the subject matter as claimed in the claims. Where dimensional ranges are given, values that lie within the stated limits shall be usable and claimable also as threshold values. For reasons of simplicity, like reference symbols are used hereinbelow for identical elements or similar elements of identical or similar function.